Dimethylamine

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No guideline followed, GLP, test method sufficiently described

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The acute toxicity by inhalation of dimethylamine with rats (strain: Charles River Crl:cd BR VAF/Plus; Sprague-Dawley derived). The route of exposure was inhalation by whole body exposure. The exposure times were 6 - 60 minutes with different concentrations (ranging from 4,620 to 19,900 ppm).

GLP compliance:

yes

Test type:

other: no data

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Dimethylamine

EC Number:

204-697-4

EC Name:

Dimethylamine

Cas Number:

124-40-3

Molecular formula:

C2H7N

IUPAC Name:

N-methylmethanamine

Test material form:

gas

Details on test material:

- Name of test material (as cited in study report): dimethylamine, anhydrous
- Physical state: gas
- Stability under test conditions: chemically stable and insensitive to light
- Storage condition of test material: normal indoor ambient condition

Test animals

Species:

rat

Strain:

other: Charles River Crl:cd BR VAF/Plus; Sprague-Dawley derived

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Inc., Portage, Michigan
- Age at study initiation: approx. 49-63 days
- Weight at study initiation: males 208-292 and females 158-220 grams on day of exposure
- Fasting period before study: Diet and water freely available except during exposure
- Housing: individual stainless steel wire mesh cages
- Diet (e.g. ad libitum): certified pelleted rodent chow #5002, Purina Mills, Inc, St-Louis, Missouri. Diet and water freely available except during exposure
- Water (e.g. ad libitum): ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C), Humidity (%), Photoperiod (hrs dark / hrs light): maintained in accordance with the recommendations contained in the D.H.E.W. Publication entitled "Guide for the care and use of Laboratory animals"

Administration / exposure

Route of administration:

inhalation: gas

Type of inhalation exposure:

whole body

Vehicle:

other: no data

Details on inhalation exposure:

not reported but figure 1 shows the schematic diagram of generation and exposure system, for more information see study trimethylamine

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

6 min

Remarks on duration:

6, 20, 60 min

Concentrations:

6 min exposure: 13,700; 15,400; 17,400; 17,500 and 19,900 ppm
20 min exposure were conducted at concentrations of 4,620; 5,940; 7,860; 7,740 and 8,860 ppm
60 min exposure were conducted at concentrations of 4,900; 5,040; 5,080; 5,120; and 5,920 ppm

No. of animals per sex per dose:

5 male and 5 female albino rats

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: at 7 and 14 days post-exposure
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other:

Statistics:

no data

Results and discussion

Effect levels

Effect levels 1

Sex:

not specified

Dose descriptor:

LC50

Effect level:

17 600 ppm

95% CL:

15 400 - 20 300

Exp. duration:

6 min

Effect levels 2

Sex:

not specified

Dose descriptor:

LC50

Effect level:

7 340 ppm

95% CL:

6 550 - 8 230

Exp. duration:

20 min

Effect levels 3

Sex:

not specified

Dose descriptor:

LC50

Effect level:

5 290 ppm

95% CL:

5 050 - 5 530

Exp. duration:

60 min

Mortality:

6 min exposure: concentrations of 13,700; 15,400; 17,400; 17,500; and 19,900 ppm resulted in deaths of 20, 40, 50, 50, 60 %, respectively
20 min exposure: concentrations of 4,620; 5,940; 7,740; 7,860; and 8,860 ppm resulted in deaths of 0, 40, 50, 50, 80 %, respectively
60 min exposure: concentrations of 4,900; 5,040; 5,080; 5,120; and 5,920 ppm resulted in deaths of 20, 10, 40, 70, 80 %, respectively

Clinical signs:

other: The significant pharmacotoxic signs noted either immediately after the exposures or during the 14 day post-exposure period were: death, laborated breathing, gasping, rales, and corneal opacities. Most deaths occured on post-exposure days 1 and 2, with one

Body weight:

For all three exposure durations body weight gain for surviving animals was generally depressed during the first post-exposure week, but recovered during the second post-exposure week.

Gross pathology:

At necropsy, eye abnormalities (usually corneal opacities) and lung congestion (red discoloration) were the significant macroscopic findings. There were no significant differences between three exposure durations.

Applicant's summary and conclusion

Interpretation of results:

Category 4 based on GHS criteria

Remarks:

Criteria used for interpretation of results: OECD GHS

Conclusions:

H332: Harmful if inhaled,
H335: May cause respiratory irritation

Executive summary:

The International Research and Developmental Corporation tested in 1992 the acute toxicity by inhalation of dimethylamine with rats (strain: Charles River Crl:cd BR VAF/Plus; Sprague-Dawley derived). The route of exposure was inhalation by whole body exposure. The exposure times were 6 - 60 minutes with different concentrations (ranging from 4,620 to 19,900 ppm). Different clinical signs, changes in body weight and also mortality (20, 40, 50, 50, 60% deaths (6 min exposure), 0, 40, 50, 50, 80 % death (20 min exposure), or 20, 10, 40, 70 and 80 % death (60 min exposures)) was reporteThis

The one hour value (LC50 = 5290 ppm = 9753.51 mg/m³) needs to be converted to a value comparable to a 4 hour LC50. This can be done as described in ECHA Guidance on the application of the CLP criteria, v5.0, July 2017, footnote c to Table 1 3.1.1 of Annex I to the CLP Regulation and Section 3.1.2.2): by dividing it by a factor of 2. (LC50 for CLP = 2645 ppm = 4876.76 mg/m³. This value is then also reported in the endpoint summary as key value.